Noiseless return for typewriter carriages



May 2, .1939. F, WUNDERUCH 2,156,418

NOISELE'SS RETURN FOR TYPEWRITER CRRIAGES 7 7 Mander/l' /BA May 2, 1939- F. wuNDERucn-l 2,156,418l

' NoIsELEsS RETURN FOR TYPEWRITER CARRIAGES Filed April 4f 1938 3 Sheets-Sheet 2 May 2, 1939- F. WUNDERLICH v2,156,418

NOISELESS RETURN FOR TYPEWRITEB. CARRIAGES Filed April 4, 1938 5 sheets-sheet 3 Has) a Patented May 2, 1,939 i NOISEIESS RETURN FOR TYPEWRITER y CARRIAGES Friedrich Wunderlich, Nuremberg,l Germany, as-

signor to the -rm Triumph-Werke Nrnberg A.'G., Nuremberg, Germany Application April 4,-1938, Serial No. 200,007 In Germany M'ay 27, 1937 'l Claims.

This invention relates to a noiseless return for typewriter carriages. Various attempts have already been made to solve this problem, but the suggestions hitherto madehave not led to a completely satisfactory result.' 'I'hus for example it has been proposed to open out by frictional action, by means of a bell-crank levera divided coupling or sleeve which is provided in the joint with teeth. The disadvantage of this appliance consists in the fact that the teeth can only en-U gage intermittently or in jerks'and that means would furthermore have to be provided for locking, which occasion a great deal of noise. Ac'

cording to another suggestion, locking or ratchet teeth arebrought out of engagement by means of -an auxiliary lever moved through the mediumv Now the object of the present invention is to provide a. completely noiseless carriage return, which will ensure a reliable disengagement of the ratchet tooth, and. this object is attained by effecting the disengagement of a divided ratchet 30 tooth under the action of the weight of the ratchet tooth or of a supplementary spring, while the engagement thereof is effected through the mediumA of a friction member actuated by the ratchet wheel. 1 35 'I'he invention is illustrated by way of example in the accompanying drawings, in which Figure 41 shofws the feeding or ratchet appliance during the retraction of the carriage;

Figure 2 shows the engagement of the ratchet 4,0 tooth;

Figure 3 shows the feeding or ratchet appliance in the writing position of the carriage; I y Figure 4 shows the feeding or ratchet applianrzeduring the striking of a key or of the space aber;

, Figure 5 showlsjav section through the feeding or ratchet body in the writing position, and

Figure 6. shows a section similar to Figure 5, during the actuation of thecarriage release lever M or of a tabulator.

In the feeding or ratchet body is slidably mounted in a guide bush IS abolt Y4, which carries at one end a ratchet tooth carrier On this carrier a loose ratchet tooth @is ro-A 1, which-1s rock-'- ably supported between conical points 2`and 3,.

(o1. 19V-ss) tatably supported about a bolt 1. The travel of the loose ratchet tooth B is limited in one direction by a stop 8, and in the other direction by a stop 9. The latter is constructed as an adjustable eccentric. ratchet tooth 6 against the eccentric 9. The stop 8 is formed by thin metal sheets II, for-thevpurpose of damping the noise of the impact. On the feeding or ratchet body I is furthermore arranged in a known manner a fixed ratchet tooth I2. The' ratchet tooth carrier 5 is subject to the pressure of-a spring I5,and swings between adjustable stops I3 and I4. A` tension spring I9 tends to keep the ratchet body I in a definite position, i. e. in which the fixed ratchet tooth I2 is out of engagement with the ratchet wheel 36. 'I'he -bolt 4, which is rigidly connected with the ratchet tooth carrier 5, is supported in a long guidingbush I6, s o that it can be displaced at right angles tothe ratchet body I. By a spring I1, which is held owing to screw means I8, the ratchet tooth casing bears on a collar Iii'l of the guiding bush I6.

In the body or frame of the Writing machine a bell-crank-lever 1 I is rotatably supported about a bolt`20. On the lever arm 2i is located a stop 22 for the loose ratchet tooth 6. To the other A tension spring I0 draws the lever arm 23 is pivote'd at 25 an intermediate lever 25B, provided with an abutmentvn'ose 2li. The free end of the kintermediate lever 25,a is pivotally connected at 21 with an arm 21S, which is integ-ral or virtually integral with a friction disc 28 supported upon the pivot 31 of the ratchet wheel. The arm 21n carries an abutment nose'26. .Into it is furthermore riveted a pin 29, which engages in an elongated hole 30 in a. friction shell 3i. Upon the latter a spring cap 33 is mounted in slots32. Compression springs 34 and,35 ensure the rubbing ofthe friction shell 3i, and also of the friction disc 28, on the ratchet wheel 36, which is. mounted fast upon the shaft 31. Positioning rings 38 and 39 vensure the position of the friction disc 38 and of the spring cap 33.

In Figurel the ratchet appliance is sented during lthe return ofthe carriage. The ratchet wheel 36 moves during this operation in the direction -of the'arrow 4I. The arm 21n is thereby carried round in the same*direction-of 'revolution by the action of the friction disc 28 and` of the friction she'll 3| until the stop 24 of the lever 25a bears on it. The bell-crank lever '2| is then rocked kthereby about its fu1crum20 in such a way that the stop 22/ass`umes the position shown in Figure 1, By the action of the spring I5, the ratchet4 tooth carrier 5 is then pressed against repre-I the stop I4, and the loose ratchet tooth 6 bears by its own weight, assisted, it maybe, by a supplementary spring I0, against the eccentrically constructed stop 9. The rounded tip of the ratchet tooth 6 is thus brought out of reach of the teeth of. the ratchet wheel 36, so that the latter can be freely rotated in the direction of the arrow l I, thus avoiding any noise.

If the carriage tension now comes into action,

in the direction of the arrow H0 in Figure 2, the arm 21a, located on the friction disc 28, is likewise rotated in the direction of the arrow 40, until its stop 26 comes against the intermediate lever 25a. A rigid connection of the arm 21e to the bell-crank lever 2l is thereby provided. The latter is now carried along in the movement of the ratchet wheel and revolves about its axis 20, so that its stop 22 bears against the loose ratchet tooth 6, and brings the latter by its movement within reach of the teeth of the ratchet wheel 36. 25 are in-one plane, and the arms 21' and 25a are therefore in the dead centre position, the

stop 22 of the bell-crank lever 2l is now immovable, without any fluctuation inthe further rotation of the ratchet wheel in the same direction.

During the further rotation of the ratchet wheel 36 in the direction of the arrow 40, the ratchet members then assume the position shown in Figure 3, in which the loose ratchet tooth 6 bears firmly against a tooth of the ratchet whee1 36 under the action of the carriage tension. The loose ratchet tooth IiV is thereby pressed against the stop 8 on the ratchet `ltooth carrier 5, asa result of which the latter iscarried along until the tooth 6 bears against the adjustable stop I3. In this position of the parts the carriage is in the writing position.

If a key is now depressed, the ratchet body I is oscillated in its bearings 2 and 3 in the direction of the arrow d2 in Figure 5. Owing to this rocking movement the ratchet tooth carrier 5 and the loose ratchet tooth 6 move in a lateral direction out of reach ofthe teeth of the ratchet wheel 36, at the same time putting in the iixed ratchet .tooth I2. The ratchet tooth carrier 5, under the action of the spring I5, now bears upon the vstop I4, while the loose ratchet tooth 6, by its own weight, or by the action of the supplementaryA -spring ""-I0,' finds its motion limited by the stop 22. This stop has a fixed position, since, as explained above, it is prevented'froni deecting by the,v straight -position of the lever arm 2'Ia and the interme- Upon furtherfeedingdiate'link or lever 25e. s the xed ratchet .tooth I2 is disengaged, and

the nexttooth of the ratchet wheel 36 bears against the loose ratchet tooth, which is then rocked, together with the ratchet tooth carrier 5, until the tooth 6 has come into contact with tabulating, the bolt 4, through the medium of a ratchet or feeding member not shown, is pressed in the direction of the arrow 43 in Figure 6, the .plane perpendicular to the fixed tooth remaining parallel to the plane perpendicular to the loose tooth. A parallel displacement of the Since the pivots 31, Zand ratchet tooth carrier 5 with the loose tooth E to the fixed tooth I2 therefore takes place. The ratchet wheel is thereby completely set free and can be rotated continuously in any direction. This method of disengaging the ratchet tooth may also be employed with a different construction of the loose ratchet tooth.

The long bearing of the bolt 4 in the bush I6 enablesthe movable ratchet tooth to have a good seat in every case.

I claim:

1. In a. writing machine`comprising a frame and a carriage reciprocabie on the frame, the provision of means for the noiseless Ireturn of the carriage, comprising a ratchet wheel rotatably mounted in the frame, a movably mounted ratchet tooth capable of engaging with the ratchet wheel but tending by its own weight to move out of engagement therewith, a movable abutment for moving the said ratchet tooth into vengagement with the ratchet wheel, and actugagement with the ratchet wheel, on the ratchet wheel being turned in the normal carriage-feed direction and moving the abutment in the opposite direction, on the ratchet Wheel being turned inthe reverse direction, so as to allow the ratchet tooth to pass out of engagement with the ratchet wheelunder its own weight..

2. In a writing'machine comprising a frame and a carriage reciprocable on the frame, the

provision of means for-the noiseless return of the carriage, comprising a ratchet wheel rotatably mounted in the frame, a movably mounted ratchet tooth, capable of engaging with the ratchet wheel but tending by its own weight to move out of engagement therewith, spring means assisting the disengagement of the ratchet tooth from the ratchet wheel, a movable abutment for moving the said ratchet tooth into engagement with the ratchet wheel. and actuating means, including friction driving means, operatively connected to the abutment and to the ratchet wheel, for moving the abutment in the direction to bring the ratchet tooth into engagement with the ratchet wheel, on the ratchet wheel'being turned in the normal carriage-feed direction and moving the abutment in the opposite direction, on theratchet wheel being turned in the reverse direction, so as to allow the ratchet tooth 'to pass out of engagement with the ratchet wheel under its own weight wit the assistance of said spring.

3. In a writing machine comprising a frame and a carriage reciprocable on the frame, the provision of means for the noiseless return of the carriage, comprising a ratchet wheel rotatably mounted in the frame, a ratchet tooth carrier,

a ratchet tooth pivotally mounted on the ratchet tooth carrier, the said ratchet tooth being capable of engaging with theratchet wheel but tending by its own weight to move out of engagement therewith, a movable abutment for moving the said ratchet .tooth into engagement with the ratchet wheel, and actuating means,

including friction Adriving means, operatively connected to the' abutment and,to the ratchet wheel, for moving the abutment in the direction to bring the ratchet tooth into engagement with the ratchet wheel, on the ratchet Wheel being turned in the normal carriage-feed direction and moving the abutment in the opposite direction.

on the ratchet wheel being turned inthe reverse direction, so as to allow the ratchet tooth to pass out of engagement with the ratchet wheel under its own weight.

4. In .a writing machine comprising a. frame and a carriage reciprocable on the frame, the provision of means for the noiseless return of the carriage, comprising a shaft 'rotatably mounted in the frame, Va ratchet wheel mounted fast on the shaft, a movablymounted ratchet tooth capable of engaging with the ratchet wheel but tending by its own weight to move out of engagement therewith, a friction member mounted loose on the shaft, an arm rigid with the friction member, a bell crank lever pivotally mounted on the machine frame, an intermediate link connecting the bell crank lever to the arm of the friction member, a movable abutment adjustablysecured to the bell crank lever and capable of -moving the movable ratchet tooth into engagement with 4the ratchet wheel. a stop on the intermediate link for limiting its movement, a friction shell surrounding the friction member, and springs urging the friction shell into frictional engagement with the ratchet wheel.

5. In a writing machine comprising a fram Yand a carriage reciprocable on the -frame, the

provision of means for the noiseless return of the carriage, comprising a shaft rotatably mounted in the frame, a ratchet wheel mounted fast on the shaft, a movably mounted ratchet tooth capable of engaging with the ratchet wheel, but tending byits own weight vto move out of engagement therewith, a friction member Ymounted lose on the shaft, an arm rigid with the friction member, a bell crank lever pivotally mounted on `the machine frame, an intermediate link pivoted atone end to the arm of the Afriction member and at the other end to one arm of the bell crank lever, a movable abutment adjustably secured to the other arm of the bell crank lever and capable of moving the movable ratchet tooth into engagement with the ratchet wheel, means for producing frictional engagement between the friction member and the ratchet wheel, a stop on the arm of the friction member, this stop bearing against the intermediate link-When the movable ratchet tooth comes into engagement With the yratchet wheel and when the pivotal axis of the connection between the intermediate link and the arm of the fric- .tion member is in the plane containing the axis of the ratchet wheel shaft and the pivotal axis of the connection. between the `intermediate link and the bell crank lever.

6. In a writing machine comprising a frame' and a carriage reciprocable on the frame, the provision ofl means for the noiseless return of the carriage,` comprising a feeding body rockably mounted on the writing machine frame, a bearing bush secured to the feeding body, a. pivot slidable in the bearing bush, a ratchet wheel rotatably mounted in the Vwriting machine frame, a ratchet tooth carrier oscillatably mounted on the said slidable pivot, a ratchet tooth pivotally mounted on the ratchet tooth carrier, the said ratchet tooth being capable of 'engaging with the ratchet wheel but tending by its own weight to move out of engagement therewith, a movable abutment capable of moving the said ratchet tooth' into engagement with the ratchet wheel, and a friction member for actuating the said movable abutment.

7. In a writing machine comprising a vframe and a carriage reciprocable on the frame, the provision of means for the noiseless return of the carriage, comprising a feeding body rockably mounted on the writing machine frame, a bearing bush -secured to the feeding body, a pivot slidable in the bearing bush, a ratchet wheel rotatably'mounted in the writing machine frame, a ratchetv tooth carrierY oscillatably mounted on the said slidable pivot, a ratchet tooth pivotally mounted on the ratchet tooth carrier, the said ratchet tooth being capable of engaging with the ratchet wheel but tending 'by its own weight to move out of engagement therewith, a friction member mounted loose on the shaft,V an arm rigid with the frictionmember, a bell crank lever pivotally mounted on the machine frame, an intermediate link connecting the bell crank lever to the arm of the friction member, a movable abutment adjustably secured to the bell crank lever and capable of moving the movable ratchet tooth into engagement with the ratchet wheel, a friction shell surrounding the friction member, and springs urging the friction shell into frictlonal engagement with the ratchet wheel.

FRIEDRICH WUNDERLICH. 

